A Soul Nobody Knows
by Castanera
Summary: Saitama is a spiritually aware human who became a hero for fun, he helps the souls to not be eaten by evil spirits called Hollows. However, he became so strong that no hollow in Karakura Town was strong enough to at least gave the caped baldy a good fight. Will Saitama find this worthy opponent in this supernatural world he lives in? Or will this be another disappointment?
1. Chapter 1

**Hello guys, OPM and Bleach fans. Castañera in yet another fanfic for this website!**

**I have been thinking of making this crossover for a while, and after watching OPM Season 2 I decided to write it while I'm not very inspired in continuing my other fics. But I'm doing anything but abandoning the already mentioned fanfics!**

**Without anything to say, enjoy!.**

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It was a calm night in Karakura Town, it was peaceful for the people who were either sleeping or outside on the streets minding their own business.

However, that could not be said in the same way for the souls from the dead people of the town, who were always there watching you, and impossible to been seen by the human eye. One soul on specific was at this very moment a possible victim of a hungry hollow.

A tiny soul with an appearance of a kid with not more than 10 years old, it was always a mystery in why the hell there were so many ghost children in a happy modern town like this, but that doesn't matter right now. And the reason that he wasn't having a good time is simple, he's very unlucky.

The plus was running as fast as its legs could take him, running away from a big bipedal hollow who was chasing the poor soul as it laughs like a maniac, with a distorted voice that terrorizes any soul when they hear it.

Like it was already established, the soul was very unlucky since it had nothing else to do as a spirit, it decided to walk on the streets. But that peaceful walk ended up becoming into a hunt, and he was the hunted.

Both spirits ran through the several empty streets of Karakura Town, the victim tried to outrun the hollow but it failed, it tried to outsmart the hollow by running in several narrow alleys but it didn't work. The plus tried everything but yet it failed in getting away from the hollow

Like the hollow has foreseen, the spirit became tired and out of breath. Its legs were now weakened and it couldn't stand anymore.

The plus wanted to scream but it was so tired to do so, talking didn't seem to be the way to make this hollow change its mind. Once a hollow targets a soul to eat, it will devour it or die in the attempt, and the second option wasn't possible if a shinigami hasn't interrupted the hunt like they have been doing for thousands of years.

The hollow smiled as he stood in front of the young spirit. The plus saw directly on the hollow's yellow eyes, completely petrified by the intimidating figure.

"That was a good chase" The hollow complimented and gave the plus a chuckle.

"But now..." It continued smiling widely, "It's time to feast!".

The claws of the hollow began to come closer to the poor spirit, who in panic crawled backward in an attempt to not be in the range of the monster's grasp. But its back touched the wall behind him, making him unable to get away any further from the hunter.

When the giant hand of hollow were close enough to its prey, it closed its hand and the hollow chuckled in victory. But then it frowned in confusion.

"What the-?..." It felt nothing inside of its hand as if it didn't catch anything at all with its own hand, it opened its hand to check what he just caught, and it was nothing, just mere air.

Realizing that he just lost sight of the spirit, he tried looking at its surroundings. And then it saw him. A bald man in a yellow suit with a white cape, red gloves, red boots.

On his hands, he had a surprised and relieved spirit, the same spirit that the hollow was chasing the whole time. But how? The hollow didn't seem to even saw him coming, or getting that soul away from him.

"Who are you?" That was what the hollow demanded to know. It already knew it wasn't a Soul Reaper or even another dead spirit of some kind, it was a simple human.

The bald man let go of the soul he had on his hands and turned to the monster that was in front of him, "Just a guy who helps ghosts for fun" The human replied with an emotionless stare.

"What?" The monster exclaimed not believing in how that idiot in front of it responded, especially in the part of 'fun'.

The hollow stopped thinking on the man's motives on opposing the evil spirit and said, "It doesn't matter, once I eat your soul, I will become stronger, and then I will hunt down that soul you stole from me to then move forward in my evolution as a hollow. And then-".

"Shut up!" The hero exclaimed interrupting the hollow, utterly uninterested on the little story that the hollow was narrating, "I will become this, I will become that...I've heard the same exact story from many other guys like you. All of you are just the same!" He complained.

"Can we just start fighting? It hasn't been a good day for me" He requested, and such request made the hollow's eyes narrowed and gritted its teeth, "You filthy human...being disrespectful to a hollow as if you were strong enough to beat me!" It was very clear that the bald man just angered the violent tiger that is the evil spirit.

"I just decided, I was thinking of simply eating you, but now I decided that I will torture your soul until you've become nothing more tha-"

It was interrupted again, but this time its whole upper body was blown away by the fist of the human, the impressive punch was strong enough that it was even heard from there to almost heard through almost the whole town. And with that, the hollow's mouth was shut for good this time.

The soul that the human saved stared at him in complete awe, as the bald hero himself looked incredulously at his fist, the same one that finished off the hollow.

"Not again!" The hero exclaimed, totally saddened and frustrated, "All it took was one punch!".

* * *

It was another day in Karakura Town, in an apartment where a bald man lives. Saitama broke by accident his alarm clock with his fist. He really should do something about it to stop himself from destroying any of his clocks. Saitama yawned before getting off the bed and walked to the kitchen, with that emotionless look on his face which he calls it his 'normal face'.

He opened the curtains of the dining room and saw the sun being in the middle of the sky.

'Did I almost just slept this whole morning?' He asked himself as he lifts an eyebrow.

After Saitama made that mistake, he prepared some eggs and bacon. After finishing in cooking the breakfast he started in eating it without anything on his mind. Except how he wasted his time in searching any of those monsters last night.

Like any other of those child-eaters he has encountered before, his fights ended up with a single punch courtesy of Saitama's fist. But that wasn't always like that.

'How did all of this even happened?' Saitama thought as he closed his eyes and began to wonder about those questions, and fortunately, he remembered clearly like the sky.

Saitama is a very special human since the day he was born, he had an ability that if he ever shared that secret to anyone of his classmates in school, they would consider him crazy. That ability is basically being able to see ghosts.

He could see spirits from babies to teenagers, and even elders, he could even hear their conversations. Some of them were interesting and others were a big pain, probably the only bad thing about having such powers.

And if you asked him, no, he didn't have the chance to see a hollow when he was a child. Which it was in fact good because he would be traumatized by now and became more introvert than he was already.

And also when he reached adulthood, he met his first evil spirit or hollow who was attacking a spirit in a park after failing in getting a job. It was also the same day when he decided to become a hero, not a hero for Karakura Town but more likely a hero for those ghosts.

Why not be a hero for the citizens? Well, he didn't actually want to get himself in trouble so afterward a cop would oblige him to pay a damn penalty only because he wore a costume in the streets, and be confused for a cosplayer wouldn't make it better.

And that's when he began his so-called 'intense training'. It consisted of doing 100 push ups, 100 sit ups, 100 squats, then a 10-kilometer run every single day. It took him 3 years to achieve the great strength he now possesses.

But after the first year and a half of intense training, he became completely bald at a very young age. Another disadvantage added to his list. The bright side was that he has now become strong!.

As for his hero costume...he found a pajama with a nice looking white cape, the clothing that was now Saitama's hero suit was located beside of a garbage can in a place that was called 'Urahara Shop'. Like somebody once said, "The trash of a man, is the treasure of other" or something like that.

'And now that I think about it, what are they even selling?' That gave intrigue to the hero, he really should take a good look at the shop another time.

And now it was time to decide when to patrol, either daytime or nighttime?.

He didn't like to not only his bald head being pointed at by some random people and kids. He didn't exactly care to be insulted in any way but being reminded by everyone that he is bald every time was another level of insulting. Going at night would also decrease the possibility to cause a lot of attention, but he could be arrested and be accused of vandalism if any cop saw him running in the rooftops in a suspicious hero suit.

So patrolling only in night appeared to be the best option he had even with those flaws that he pointed out.

And now that he had the power, the clothes, and the determination! He went outside on a dark night to make his debut!.

Saitama jumped from roof to roof of several buildings looking for any spirit to be saved by him, he spotted a pack of hollows whose were about to attack the soul of a girl, he lost no time and attacked the hollows.

But for Saitama's surprise, one of them was defeated with a single punch. He ignored it and assumed that they were simply weaker than him and the rest of the pack, but then he fought another, another, another, another, and all of them were slain with a single damn punch!.

The spirit of that girl he saved showed their gratitude, the bald hero was very flattered by the appraisal, but he didn't felt like he has accomplished anything, instead, he began to the thought that he didn't do anything at all but punch in that guy's face and that other guy too.

And from this day he kept patrolling every single night, in a search for a worthy opponent to fight and feel the adrenaline he once felt on his early days!

But unfortunately, no matter how much he tried he never has found anyone stronger like him or someone that could at least give him a good fight. It was saddening but why was he kept doing all of this hero thing when Saitama is bored? Well, the answer is simple...

The hero heard the growling of nothing more, nothing less than a hollow. "Another one of those things?" Saitama wondered kinda surprised, never on his time as a hero had any of those creatures looking for him. It was unusual.

Suddenly the evil spirit broke the roof of the bald hero's apartment and entered the same room as the hero and grinned, "You're a strong soul! I will-!" Just like what happened last night, a hollow was interrupted when a fist broke its entire white mask and the head exploded afterward, eliminating another evil spirit.

Saitama stared angrily at the what's left of the hollow before threatening, "You're going to pay for my ceiling!". A that was unnecessary because let's be real, hollows don't have any money on them and that hollow it's dead already.

The hero thought it was over until he heard several growls, screeching, screams from those hollows outside of the apartment.

"Something must be happening outside" Saitama wasted no time and changed to his hero clothes, afterward he jumped out of his apartment through the hole where the spirit who the bald man defeated came from.

He admired Karakura Town and saw many hollows reuniting in several places in the town, "Woah" The what impressed him was the absurd amount of hollows there was, it wasn't just a pack like the ones he usually fights. They're hundreds, maybe there are even a thousand.

"Maybe I should get to the bottom of this, someone may get hurt" He decided but before he began to explore the now attacked town, he got surrounded by more hollows, one more intimidating than the other.

He heard the hollows saying stuff like, "An easy soul for me!" Or "It's your end!". But instead of listening to any of their statements, Saitama smiled.

This might be a great chance to find a powerful one!.

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**So this is the end of the first chapter of this crossover!.**

**It appears that the Karakura Town is being attacked by a lot of hollows, and the question remains on why?.**

**Can Saitama get the bottom of this situation? Is he going to find a powerful opponent on this violent assault?.**

**Find out in the next update, If you find any problem you can ask me. Any reviews are appreciated, those can help me in future writings. Goodbye!.**


	2. Chapter 2

**It's been 84 years since I updated a story, or do anything at all. But at the end of the day, I still publish something so it doesn't matter.****And also, before starting with the reading I have to say that I'm really thankful with the feedback, I just published a single chapter and it has became the fanfic with the most favorites and follows of my entire profile.****So once again, I'm so thankful and enjoy the chapter.**

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The presence of the hollows who surrounded the hero made the said hero feel a very recognizable feeling, excitement. There are hollows of different colors and sizes, and the fact that there are even more in the town only makes him raise his expectations. He wondered if there will be someone strong like him between the crowd.

His thoughts were interrupted by the sight of a dangerous red blast that was shot from the mouth of a hollow, Saitama leaned backward dodging the bullet quite easily.

The next attack came from two hollows who had a very similar appearance, both had a muscular figure and they possess a gorilla-like white mask, the only difference was the strange markings on their masks. They attempted to hit the hero with their own fists, and when they made contact with him, their attack was ineffective and it didn't even make him move a single centimeter from his spot.

The hero proceeded to deliver a punch at the two hollows who couldn't handle the impact and both of them exploded in several pieces, slaying them in the process much to Saitama's disappointment.

They looked kinda cool and they were working together, maybe the two hollows were friends or even brothers. Either way, they are already defeated.

The next attacker was a mantis-like hollow, who jumped into the hero with its large blades aiming for the head, but in the end, the hollow was the one who ended up being headless. It only took one punch for that to happen.

The battle continued for 10 minutes, the whole thing can be summarized with Saitama defeating every single hollow who dared to attack him, in a single punch.

'This is getting old...' That's what Saitama thought as he punched another random hollow who tripped right behind the hero.

Saitama isn't getting tired, but he's likely getting bored and disappointed. The excitement he once had, it perished in a matter of seconds.

He looked at the attackers again, the number of the enemies clearly decreased yet many are still attacking him and not only that, there are even more of them in several places of Karakura indicating that the long battle was far from over.

"Hey, when are you guys leaving? Don't you people have anything else to do?" Saitama asked with a bored look, he was so bored that it was very noticeable for anyone present.

"You know, like a job? hobbies?" The only response he got was screams and shriekings, courtesy of the hollows. That was until a hollow from the bunch exclaimed, "We won't leave until one of us takes your soul!".

The hero sighed, and afterward, several hollows jumped into Saitama in a pointless attempt of claiming his soul. And the results were obvious.

Somewhere in Karakura Town far in the woods, that is one of the several places where the hollows have gathered to hunt the strongest souls around. On this case is a Quincy and a Substitute Shinigami.

"Alright! Who's next?" Exclaimed Kurosaki Ichigo, the orange-haired teenager who wields his Zanpakutõ and cuts in half another hollow.

It has been a rough day for Ichigo, this classmate revealed to him that he was a Quincy and challenged him on that dumb bet.

A bet that consisted of the Quincy using some kind of bait that supposedly attracted hollows, the game ends when all the hollows are eliminated. The winner will be the one who kills as many hollows possible.

As the Shinigami swung his massive sword at another hollow, Ishida Uryu shots a huge amount of arrows at different hollows who were on his range in a short period of time, causing the destruction of said spirits.

His day didn't go exactly like he planned since he acknowledged about Ichigo's powers, he planned a competition to prove at once that his services as a Shinigami were worthless. But something was wrong with the bait he used, normally, it should only attract only a few evil spirits but instead, countless hollows invaded the World of Living.

Now he had no choice other than teaming up with Ichigo, not giving importance the hate he had for the Shinigami or his pride as the last Quincy.

"Alright, next!" Ichigo bellowed, catching the attention of several hollows. Even if he was slightly beaten up and bloodied, he could keep going.

As the hollows approached the shinigami, Ichigo jumped with his weapon in hand, he spun and decapitated the half of the hollows whose chase him. He landed on his feet just in time to block an incoming punch from a hollow.

"Haa!" He yelled as he did an upward swing, cutting the hollow in half. He then avoided a volley of arrows, Ichigo noticed that Uryu was getting a little tired as the time passes.

"Hey Ishida, how do you feel about this stupid bet now?" The orange-haired boy asked as he wiped some sweat from his face.

Ishida looked at his rival, "This shouldn't be possible..." He said. "The bait shouldn't have brought this many hollows!" Uryu continued feeling a bit ashamed of himself, making the other student raise his interest.

"So you aren't that crazy after all..." Ichigo said somewhat relieved, the moment he saw the great number of hollows invading Karakura, he considered the purple-haired teen a psycho for using that bait without considering the lives of others. Good thing it was some sort of accident.

After taking down another quintet of hollows, to go along with the last 20 or so they have killed before, Uryu felt an immense amount of reiatsu, "Kurosaki!".

Ichigo was about to ask what does his Quincy friend needs, but then he realized the problem once he noticed a large tear was appearing in the sky.

* * *

Somewhere not far away from the two teenagers, Kuchiki Rukia stared at the tear in the sky. It started to open wide enough to reveal a large pointy-nosed white mask, it could be seen a sheet-like body through the hole.

"That's...what's that?" A mod soul called Kon asked, who is just as shock as the Shinigami on a Gigai.

Rukia replied, "It's a Menos".

"A Menos?" Kon repeated, not very familiarized with the term, he wondered if that was a type of hollow or it was its name.

"It's a gigantic hollow said to be born when hundreds of hollows pile atop each other and intermingle". The shinigami explained.

"It's not something that a single shinigami can fight alo-!" Rukia stops with his statements when she saw the Quincy who challenged Ichigo, and Ichigo himself recklessly charging at the gigantic hollow.

'What the hell is he thinking?!' She wondered. Even the Quincy thought the same thing and the words, "How reckless" escaped from his lips.

Rukia ran leaving behind the mod soul to catch up with Ichigo in an attempt to stop him in his suicidal attack. "H-Hey! Hold up!" Reacted Kon as he followed his so-called 'sister'.

Rukia was way too slow and witnessed how the Menos Grande kicked Ichigo with its only leg that was outside of the tear, luckily the hollow didn't kick him with all its might or too far away from the zone. The substitute fell to Uryu's side with a trail of blood falling across his forehead. The Quincy also noticed the girl coming along with that mod soul of theirs.

"Idiot, what were you thinking?!" Rukia scolded the teen, who replied as he put himself on his feet, "Well I thought if I cut it away piece by piece from the feet up, the head would come down".

"You must be kidding me!" She exclaimed, not believing that Ichigo had such a way of thinking, "Hey! At least I'm trying my best in taking down those hollows! Where were you anyway?!" Ichigo shot back.

"Hey, we must form a new plan to defeat that hollow" Uryu reminds them about the Menos Grande's presence in an attempt to stop the pointless discussion.

"Yeah, yeah..." The orange-haired teen lazily said giving himself a break from Rukia's constant scolding while the girl crossed her arms but still agreed.

Kon stared for the eleventh time at the menos, who was slowly getting out of the garganta. It was very unsettling. It was all good when the hollows were only the size of two humans, they at least didn't look that intimidating, unlike this massive black being.

The question remains in how could they beat such strong hollow. And the fact that everyone was tired like Ichigo and Uryu didn't help at all. Talking about his friends, he glanced at his allies who were planning something that he wasn't listening to. Something about using Ichigo's spiritual pressure? He had no clue.

And that was when Kon sensed more reiatsu near them, it came from something, no...somebody. But who? It was that guy called Urahara? No, that somebody's reiatsu isn't one he has felt before.

The mod soul was about to alert the rest until a certain hollow growled loudly.

Everyone looked at the same menos grande but this time it's right arm was severed and fell to the ground. "Who's that?" Wondered Ichigo, surprised just like the rest, a stranger stands on the air where the breeze made contact with its spiky blond hair.

Uryu noticed that it is also a shinigami, thanks to the black shihakusho it wore. Also, something very noticeable was the several mechanical features that covered some parts of its body, for example, its arms.

"You're the one with the highest reiatsu out of all the hollows of this town" The intimidating blonde noted as the Gillian tried to grab the young man with its other hand, but the shinigami was quicker and with his exposed Zampakutõ cut the white mask in two.

The hollow let out a shriek before falling and started to fade, purified by the mysterious Shinigami.

"Incredible, it only took him only two strikes..." Uryu commented quite relieved, however, he noticed that the powerless shinigami looked at the stranger differently.

Ichigo noticed the Quincy's gaze and noticed the same thing about Rukia's expression, she was afraid.

"Rukia?" The said girl turned around. "We must go, now!" Rukia exclaimed agitatedly. Before the two teenagers could reply, the mysterious shinigami spoke.

"So this is where you've been, Kuchiki Rukia?" The blonde asked before he in a single instant, shunpo'd in front of our heroes, he glared at Rukia with clear seriousness.

Uryu commented obviously surprised, "He's fast! way faster than me or Ichigo".

"Genos, why are you here?" She asked while at the same time hide her nervousness to the shinigami who is now called Genos.

"I came to the world of the living as soon I sensed a massive amount of hollows in a single place" Genos replied, "It was a huge coincidence to find you here as well" The cyborg added as he pointed at Rukia with his metallic finger.

"Who even are you?" Ichigo asked holding tightly his Zampakutõ. "I could ask you the same thing" He replied as his yellow robotic eyes began to scan his 'fellow shinigami' in an attempt to find out which squad is Ichigo from, but he found no results.

It confused the robot-looking spirit at first, but the situation they were in made it clear as day, or at least in the mind of Genos.

"Based on your ridiculously low reiatsu, I can deduct that this human somehow managed to steal your powers" He guessed making the substitute shinigami to huff in annoyance at the accusations. The cyborg definitely didn't know the real story.

The words said by the shinigami made the black-haired girl deny his claims, "N-No, that's not what happened!".

The cyborg shook his head, "It doesn't matter, either way, you both are coming with me to the Soul Society. Once there, you will be judged for breaking the rules" He stated coldly. This obviously made Kon gasp, not liking the idea of his sister being kidnapped.

Rukia was about to protest, avoid a possible conflict. But Ichigo stepped in, "We are not going anywhere," Ichigo said giving a daring stare at the cyborg, clearly challenging said shinigami.

"Idiot, this is a fight you can't win! He's far stronger than most if not every lieutenant!" She exclaimed in an attempt to stop the teen's tracks, but Ichigo instead ignores her.

Ichigo pointed with his sword at the blonde before exclaiming, "If you want a fight, I'll make sure to kick your ass!" At the end of his sentence, Ichigo smiled.

The shinigami stayed silent for a few moments before pointing out, "You're low in reiatsu and tired after fighting those hollows, not to mention to your several injuries".

"Do you really think I care about that?" Ichigo retorted not giving much importance to Geno's words.

* * *

**Even after defeating a memos grande, they still have a greater problem. Can our heroes get out of this conflict Who is this strange shinigami?**

**Find out in the next update of this fanfiction.**


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